Pressure-gage



(No Model.)

,A. C. MEADY & W. A. DODGE.

PRESSURE GAGE.

No. 373,532. Patented Nov. 22, 1887.

' TINITED STATES PATENT OFFICE.

ALBERT C. MEADY, OF SOMERVILLE, AND WILBUR AUSTIN DODGE, OF BOSTON, ASSIGNORS TO THE CROSBY STEAM GAGE AND VALVE COMPANY, OF BOSTON, MASSACHUSETTS.

PRESSURE-GAGE.

SPECIFICATION forming part of Letters Patent No. 373,532. dated November 22, 1887.

Application filed July 18, 1887.

Serial No. 244.625. (No model.)

T0 (LZZ ZUhOHZ/ may 0072087721.

Be it known that we, ALBERT CEoIL lVIEADY and WILBUR AUSTIN DODGE, citizens of the United States, residing, the former at Somerville, county of Middlesex, and the latter at Boston, in the county of Suffolk, and State of Massachusetts, have invented certain new and useful Improvements in Steam-Pressure Gages; and we do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

Figure 1 is a front elevation of a steampressure gage with the cover of its case re moved. Fig. 2 is a transverse and vertical section of said gage.

The object of our invention is to provide means whereby the point of the hand of a steam pressure gage may be made to correctly indicate the pressure of steam in a boiler.

In testing and adjusting steam-pressure gages of the class hereinafter described itis necessary to have some means whereby adjustment of the mechanism which is connected with the ends of the expansible tube (and by which the index-hand is caused to move around the dial) can be effected, so as to compensate for the variation in the said expansible tubes,

the arms of said tube in one gage being moved apart less when submitted to a certain pressure than the arms of a like tube in another gage of the same construction when submitted to the same pressure. For instance, take two gages of the same construction shown in Fig. l, and before any adjustment of the parts. Submit each to the pressure which its dial in dicates, say, one hundred and fifty pounds. The point of the hand in one will stop short of the one-hundred-and fifty-pound mark, and in the other it will be carried past said mark, owing to variation in the expansible tubes, one perhaps being thicker in some portions than the other. To obviate this is the purpose of our invention, and when the handy stops short of the mark indicating the pressure we move the pivot h toward the fulcrum g to increase the throw of the longer arm ofthe lever G, and when the hand more than indicates the pressure we move the pivotaway from the fulcrum 9, so as to diminish the movement of the longer arm of said lever G.

In the drawings, A denotes the case of a steam-pressure gage, and B the Bourdon expansible tube arranged and supported insuch case in manner as shown, the tube at its middle or lower part opening into a tubular head, 0, which is secured to the case, and has projecting down from it through said case a short tube or pipe screw-threaded on its outer periphery, as shown, to receive a coupling to connect it with a pipe proceeding from a steam-boiler.

Secured to the back of the case of the gage is a chambered supporter, D, having formed in the inner end of its chamber a bearing, a, to receive one end of a shaft, E, on which the hand F is secured. The other or outer bearing, 1), of the shaft is an adjustable one, as shown, and is secured in place bya setscrew, 0. Between its bearings the shaft is provided with a pinion, d,,to operate with a rack, e, pivoted atf to the lower end of a lever, G, said lever being fulcrumed at g to cars H,projecting from one end of the expansible tube. Aboveits fulcrum the lever is formed with a bend or deflection, i, the object of said deflection being to allow the pivot h to be arranged in line with the pivots f and g, as it is desirable to have them as nearly in line as is possible, and to the upper end of said lever is secured by a rivet, [0, two links, Z, to which and to ears I, extending from the other end of the expansible tube, is pivoted at hand m a link, a, as shown.

The links Z are pivoted to the lever G, but bear against its sides with sufficient friction to hold them in any position to which they will be liable to be moved in either direction to vary the distance between the pivots h and g, for the purpose hereinbefore set/forth.

Secured in the flange of the supporter D,and so as to project over the rack and keep it in engagement with the pinion d, is a post, K.

Having described our invention, what we claim in a steam-pressure gage is- 1. The combination of the expansible tube B, supported as described, and provided at its ends with ears H I, as shown, the link at and lever G, pivoted thereto, respectively, and connected with each other by the links Z, said lever having the deflection i, as shown, the

rack e, pivoted to said lever and held in con- 3. The lever G, provided with the bend or deflection i, and the links Z, pivoted thereto, and the post K, in combination with the link n, ears H I, and expansible tube B, supported as shown, the rack e, supporter D, shaft E, adjustable bearing b, set-screw a, pinion d, and hand F, all being arranged and to operate substantially as set forth. 7

4. The lever G, provided with the bend or deflection i, and the link or links Z, pivoted thereto, the post K, and supporter D, provided with fixed and adjustable bearings, as described, in combination with the link n, ears H I, and tube B, supported as described, the rack e, pinion d, shaft E, and hand F, all arranged and to operate essentially as set forth.

In testimony whereof we affix our signatures in presence of two witnesses.

ALBERT O. MEADY. WILBUR AUSTIN DODGE.

Witnesses:

S. N. PIP R, G. F. DANIELS. 

